


Love Triangle Beat

by btamamura



Series: NatSyoAi [1]
Category: Uta no Prince-sama
Genre: Blow Jobs, Coming Untouched, Established Relationship, Frottage, Grinding, Hand Jobs, M/M, Non-Penetrative Sex, Rutting, Self-Indulgent, Shameless Smut, Threesome - M/M/M, Voyeurism
Language: English
Status: Completed
Published: 2019-03-04
Updated: 2019-03-04
Packaged: 2019-11-09 06:18:47
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,179
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17996531
Author URL: https://archiveofourown.org/users/btamamura/pseuds/btamamura
Summary: Natsuki has a need when Ai comes to visit. Somehow, Ai finds himself joining Natsuki and Syo's activities and learns more than he'd expected, including how deep his relationship with the pair truly runs.Lots of coarse language courtesy of Syo.





	Love Triangle Beat

**Author's Note:**

> Disclaimer: I do not own Uta no Prince-sama or any canon characters. They are the property of their respective owners.
> 
> Notes: I lowkey OT3 the Kawaii Trio. There, I said it. And after a discussion in a NSFW chat for the series, I found myself starting to write a lemon involving the three of them. Natsuki and Syo are already in a relationship but Ai will be joining.
> 
> Warnings - slash, possible OOC, explicit sexual content, lots of swearing thanks to Syo.
> 
> I hope you enjoy!

"Syo-chan, I'm at my limit..." Natsuki had his arms around Syo's waist and his head on his shoulder. "I need you..."

Syo blushed lightly at hearing how bluntly Natsuki had expressed such desires. "I get it, okay? But, Ai will be over soon. We can't just..."

"Please, Syo-chan..."

He sighed. "Will making out be enough for now? Then, after Ai's gone, we can pick up from where we left off."

He nodded. "Alright." He pulled back. "Syo-chan, I don't know what's come over me today."

"We all get a bit needy sometimes, it's fine."

His green eyes shone as he slowly nodded. He moved in, cupping Syo's cheek and bringing their lips together.

Syo reached a hand to the back of Natsuki's head and ran his fingers through his hair. He heard Natsuki let out a soft moan as he opened his mouth in silent permission to deepen the kiss. As Natsuki's usually calm kisses became desperate, he realised that just making out would not be enough after all. It seemed his need to go further was pretty high on the scale that day.

Natsuki picked Syo up and maneuvered him to his lap, having the younger straddle him, all without breaking the kiss. He rolled his hips upwards to express to Syo just how much he needed his touch.

Syo broke from the kiss as he felt Natsuki's groin contact his own.  _He's hard..._  "Natsuki..."

He buried his head in the crook of Syo's neck. "I'm sorry. I'm so sorry. I know Ai-chan will be here any minute, but..."

"Hey, it's alright. I'm not mad at you or anything."

It was at that point Ai entered their room, permission to do so granted prior to his arrival. He saw the pair on the sofa. "I appear to have come at a bad time."

Both blonds looked his way, cheeks red - Natsuki's more than Syo's. "Ai! It's...yeah, exactly what it looks like."

Ai sighed and moved to sit elsewhere. "I can only visit for now. But, I can detect that stopping is not an option for you two." He focused his gaze on Natsuki in a silent  _especially in your case. “_ Continue as you were, I shall wait for you."

That got Syo's cheeks blazing hot. "Whoa, wait, what?! Um, Ai, we're not just making out here, I'm sure you figured that out."

"I have and am well aware of the situation. As such, I will wait."

"B-But..." As much as Syo protested, the thought of someone watching was actually kind of hot. But, what did Natsuki think?

Natsuki looked to Syo, eyes moist. He seemed to be pleading that they do continue right then, Ai's presence didn't seem to be an issue.

"If you're up for it, Natsuki..."

"Please, Syo-chan. Even if Ai-chan is watching, I need you."

Syo leaned close to Natsuki and whispered in his ear. "I'm getting so fucking turned on right now. I didn't know I needed this."

"Needed what?" Natsuki kept his voice soft.

"Someone watching us."

"Syo-chan...if...if Ai-chan..."

"Yeah. If he wants to, he can, I'd like if that happened. You?"

"I'm the same."

He nodded then captured Natsuki's lips, resuming the desperate, passionate kiss from earlier. He rolled his hips down to let Natsuki know he was affected physically as well.

Natsuki broke from the kiss and let out a quiet sound in response as he rolled his hips upwards again in retaliation.

"F-Fuck, Natsuki..."

Ai contined to watch them grinding their hips against each other. He cocked his head, wondering how that could cause such delight in the pair while fully clothed. He knew about intercourse, but that was about as far as his knowledge went. 

"Syo-chan...we need..."

"Yeah." He slid off Natsuki's lap. Feet on the floor, he started undressing. He slipped his shirt above his head, mindful of the clips holding his right bangs. He put his thumbs in the waistband of his trousers and turned to Ai with a smirk. "Like what you see?"

Ai could feel he was heating up slightly. He huffed out a sigh. "I don't see much right now. The teasing would have worked better if you were about to pull down your underwear. Much like Natsuki has done."

Syo turned to Natsuki to see he was completely bare. If he wasn't already aroused, he imagined he would've been by the sight alone of Natsuki's hardened penis. 

Natsuki looked to Syo. "Syo-chan..."

Syo quickly removed his trousers and underwear, then returned to Natsuki's lap. He brought their mouths together as he felt Natsuki's member against his, then grasped by a large hand. He moaned and whimpered at the sensations.

Ai rose from his seat and changed position so he could have a better look at what they were doing. He cocked his head once more as he saw their kiss break. "What are you doing?"

Natsuki was panting and unable to respond.

"Frotting...ahh, shit, feels so good..." Syo answered, chest rising and falling with each pant.

"It feels good?"

Syo turned to Ai. "You ever jacked it?"

"Jacked it?"

"Spanked the monkey? Choked the chicken? Got yourself off?"

Natsuki caught his breath. "Masturbation."

"No. I believe I may have heard of it but have not done so myself," Ai replied. His temperature seemed to be rising again.

"Ahh, fuck... Damn, Ai, you're missing out...shit, Natsuki!"

Ai's eyes widened at that cry. "Did Natsuki hurt you?"

"N-Nah, that was what I...oh shit, that's what I liked." He reached his hand to Ai.

Not quite understanding why Syo reached for him, Ai grasped his hand. "What do you want, Syo?"

"Ai...I wanna touch you too."

His temperature spiked enough for his cheeks to turn pink. "Syo, what are you saying?"

"Ahh, good idea, S-Syo-chan...I bet Ai-chan will be so...mmm...cute!"

Syo smiled. "Ai, do you want to join in too?"

"Why me? Aren't you with Natsuki?" Ai questioned.

"Yeah, but we want to do it with y-you too...shit..."

"Mmm, Ai-chan, s'il vous plaît?" Natsuki added.

Syo chuckled. "The French again...god, I'm close!" He looked to Ai again. "You don't have to say yes if you don't w-want to, b-but you're w-welcome to j-join in if y-you want..."

Ai considered his options. It seemed that sexual activities could also be used for bonding. Even if he wasn't romantically involved with them, they wanted to be more intimate with him. The experience might also help him in the future. "If I am welcome to, then I would like to accept."

Natsuki beamed, despite looking exhausted from working himself and Syo to orgasm. 

Syo grinned. "Well, you'll need to take your clothes off too. Better access that w-way."

Ai nodded, releasing Syo's hand from his grasp. He stood upright and started swiftly removing his clothing. Within a minute, he was in the same state of dress as his kouhai. He looked down and saw his physical condition matched the pair.

Syo's smile softened. "Yeah. Knew it."

"Ai-chan, your penis is so cute!" Natsuki added.

Syo laughed. He was relieved Natsuki hadn't said that about his own their first time, but it seemed he was in agreement regarding Ai.

"Syo, you can touch me if you'd like."

Syo nodded. He had Ai step closer before reaching for his penis. He ran his index finger along the length and saw it twitch. He and Natsuki knew the truth about Ai's composition, so he was slightly amazed at how realistic that reaction was. "Ai..."

Natsuki leaned close to Syo. "Can I kiss him?"

Syo nodded. "If I can too."

Natsuki nodded. "Ai-chan, can I kiss you?"

The younger idol nodded. "Very well." He leaned close to Natsuki as Syo gently grasped his member.

"Have you kissed anybody aside from when acting?" Natsuki asked.

Ai shook his head.

"I'll go slow then. Pull away if you want to stop."

"We take consent seriously," Syo added. "The instant there is a stop or anything to that effect, that is what we'll do."

Ai nodded. He closed his eyes as Natsuki allowed their lips to meet. True to his word, Ai noticed Natsuki was taking it slow. It was starting with gentle pecks. Ai knew those kisses, he'd used them. He made his move to reciprocate. He felt Natsuki nibble his lip.

Syo released Ai's member, it was dry and he didn't have lube within reach. He decided he needed to help it get wet. He stretched up slightly and placed a kiss on Ai's chest, his tongue flicking out.

Ai shivered at the kiss but broke from  the one he was sharing with Natsuki as he felt Syo brush his tongue against his nipple. He let out a soft gasp, but instead of pulling away, he arched into it.

Natsuki chuckled. "Ai-chan, so cute...so...ohh, Syo-chan, Ai-chan...I'm going to come..."

Syo tensed as he felt Natsuki pulse against him. "Yeah, I can feel it."

Ai pulled back. "Then, come, Natsuki. Let me see it."

Natsuki gasped. "Sorry, Syo-chan, I'm unable to...hold back..."

Syo leaned close and gently kissed him. "Come for us, Natsuki."

Natsuki gasped. Syo and Ai, two men who he loved, two men he considered the cutest in the world, were about to watch him come, and the very thought of it finally brought him over the edge. "Syo-chan...ahhh...Ai-chan...coming...ahh!"

Ai watched in wonder as the stream of white spewed forth from the tip of Natsuki's penis. "So, this is ejaculation..." He reached a hand to Natsuki's head and gently started to pat it as Syo helped Natsuki through his climax.

Natsuki collaped against Syo's shoulder, trembling and panting. "Ahh...wow, that was..."

"Fuck, that was hot, Natsuki..." Syo murmured, kissing his temple.

Ai continued running his fingers through Natsuki's hair. "Thank you, Natsuki."

Natsuki sighed. "But, I came alone. That's not fair to both of you."

Syo chuckled softly. "It's fine. Something tells me you'll be hard again soon." He looked to Ai. "Ai, let's make each other come for Natsuki to see."

Natsuki allowed Syo off his lap. "Mm, I want to see that."

"Feel more confident with kissing now? I saw how it went for you and Natsuki."

Ai nodded. "I now understand how a passionate kiss works."

Syo nodded. "Good. We'll rut for now. Got more in mind for later if you're up for it."

Natsuki shifted off the sofa and moved aside so Syo could lie down and then direct their younger senpai to lay atop him. "You can also straddle if you prefer," he advised Ai, giving him a quick peck on the cheek.

Ai nodded, taking the advice into account before Syo pulled him in for a kiss. It was a bit rougher than Natsuki's but it was still pleasant. He moaned into it as Syo ran his hands down Ai's sides and cupped his bottom. He shivered at the contact and felt Syo push Ai's hips down as his own rolled up. He gasped at the feeling of Syo against him.

Natsuki sat on the floor so he could have a perfect view of what was about to happen. He reached a hand to Syo and ran the other down Ai's back.

Syo pulled Ai back in for a kiss as he reached a hand to Natsuki and grasped the hand offered. He linked their fingers and squeezed.

Ai soon pulled back from the kiss. 

"Shit, gonna come soon...Ai, you need to..."

Ai cocked his head as he realised he was at a loss of what to do.

Natsuki helped him. He directed the younger man to sit up and straddle Syo's hips so their penises would have contact. He then guided Ai's hips back and forth twice before letting Ai take it from there. It seemed Ai was really sensitive on his nipples, maybe that could help him reach the same point as Syo. He kissed Ai's chest gently, pausing at his nipples, then did as Syo had earlier.

Instead of a gasp, Ai cried out. The sensations were becoming overpowering and a new one was forming in the pit of his belly. He panted roughly as he picked up the pace, realising something would happen if he kept going. Harder. Faster.

Syo cried out as well, gritting his teeth. "Ai, are you there yet?"

"I...believe so..."

"Fuck...yeah, yeah there it is...Ai, let's come together for Natsuki."

Natsuki had sat back again. As he watched Ai and Syo groan and grind, he could feel he was starting to become erect again. The urge to masturbate to the sight was strong, but he settled with gently grasping and stroking just to ease the arousal. He wanted to do more with both of them.

"Ai...I'm coming..."

"I believe I too am about to ejaculate..."

"Ahh! Ai! Ai, I'm coming! Natsuki...!"

Natsuki focused on the pair. He saw both penises pulse and felt his own twitch in sympathy.

"Syo...Natsuki...!"

Two cries sounded at the same time two streams of white spouted across their chests. Ai kept rocking against Syo, though was much slower, only working them both through the climax. He started to fall forward but was caught by Natsuki.

Natsuki kissed them both on the lips. "Thank you for letting me see that."

Ai's panting was necessary for cooling his internal systems. He opened his eyes blearily after Natsuki pulled away from kissing him. "Those sensations were intense. Is sex without penetration always like this?" he asked once he felt his temperature had been regulated.

Syo nodded. "Yeah. There's more, if you're up for it."

"More?" Ai sat up shakily. "I don't understand. Are these acts something you'd normally share?"

"Not with everyone, no. But, it's different with you."

"Different how?"

"Heh, well, we moved quite a few steps ahead, but would you believe us if we said we were into you?"

He cocked his head once more.

Natsuki smiled softly as he wrapped his arms around Ai's shoulders. "Is it hard to believe, Ai-chan?"

"It's not that it's hard to believe. But, I am confused. If you were into me as well, why did you wait until now to let me know? As Syo said, there is an order to this and you skipped quite a few steps. The least you could have done was ask me to dinner first." He heard them chuckle at that and smiled slightly. It seemed that silly line was good for breaking tension. "In all seriousness though...why me?"

"You're cute and you always looked out for us. Even if you were blunt to the point it might have seemed like an insult, you pointing out our flaws helped us acknowledge what we needed to do to become better idols. We've always appreciated it. Ai-chan, you've always been someone dear to us, even if as a friend at first."

"Even when I didn't treat you in the same regard..."

"It took a while to get used to your personality and how you interacted with us, but we realised it's just how you are. If we don't fault Tokiya for seeming to be cold at first, why would we fault you? Then, we learned about that. We already cared about you, but it felt like we could be closer after learning something new about you," Syo added.

"We came to realise that we love you, Ai-chan. But, we didn't know how you'd respond and since you were still learning to understand human emotions, we didn't want to put any pressure on you. We're both sorry, Ai-chan," Natsuki murmured.

"While this is an unorthodox means to let me know...I'm glad you did. I can't say I know yet what my own feelings are."

"That's fine, you can take as long as you need to respond."

"Should I leave for now?"

Syo shook his head. "We want to be with you. Unless you want to leave, that is."

Ai shook his head. "I don't. I want to know more. About myself, about both of you, about these experiences."

Syo sat up and wrapped his arms around Ai's waist. "Then, stay."

"Syo..."

"If we can help you find the answers, we'll do whatever we can," Natsuki murmured.

"Natsuki..." Ai felt a warmth in his chest. He wrapped his arms around Syo and leaned into Natsuki's chest.  _Is this feeling the one they seek from me? Is this love?_

***

They had moved to the bed. Ai panted as he felt Natsuki's tongue teasing his slit. "N-Natsuki..."

Natsuki pulled away and lifted his head from between Ai's thighs. "Is that alright, Ai-chan?"

He nodded as he bit his bottom lip.

Syo embraced Ai from behind and started pecking his neck tenderly. "Does it feel good?"

Another nod. "Very good. I didn't...nn...know a mouth could feel...like this...especially here..."

Natsuki beamed. "Shall I continue?"

"Yes, do so."

He bowed his head again.

Ai leaned back against Syo. He hadn't realised just how strong and muscular the smaller man's build was. He tilted his head to grant Syo more access while forcing his legs wider apart instead of together as instinct was trying to enforce. He squeezed his eyes shut and panted more.

Syo cupped Ai's cheek and directed him to look back at him. "Ai..."

Ai's eyes opened slightly. "Syo..."

Syo brought his lips to Ai's, kissing him tenderly as he ran a hand up and down his side. He used his lips to coax Ai's lips apart then slowly slid his tongue in. He heard Ai let out a soft moan. He hoped he and Natsuki would be the only ones to ever witness Ai in such a state.

Ai broke from the kiss as he had to pant once more. "Hot, so hot..."

Natsuki stopped immediately in concern. "Are you overheating?"

Ai nodded. "G-Give me a minute."

Syo released Ai and sat back. When Ai had managed to regulate his temperature, he could move in and embrace him again, but if they had kept going while he was overheating, they'd risk causing an emergency shutdown. That wouldn't be good at all. "Take as long as ya need. If you'd shutdown just because of us, I'd feel like shit."

"We'd both feel terrible."

Ai shook his head. "It wouldn't be your fault. I am not used to these sensations so my receptors are in overdrive, but over time, my internal systems may adjust and function with more efficiency even when engaging in promiscuity." He could feel he was starting to cool down, but it was still a little too soon to resume, as much as he wanted to. He leaned back against Syo again.

"Ai..."

"We need to take it slow, but my systems have cooled enough. Natsuki, you may resume. Syo, you'll have to settle for holding me right now. We can kiss after Natsuki has made me ejaculate."

Syo blushed deeply. "Geez, I don't know whether to laugh or not. The way you put it like that is just so..."

Ai pouted. "Would you prefer I say _come_ instead?"

"It's less technical so it isn't quite as awkward."

"Then, Natsuki, make me come, then I will kiss Syo. I believe this is the best way to ensure I don't overheat too rapidly again. Enough times of overheating will damage my internal systems."

Natsuki nodded. "We'll be careful, Ai-chan. No matter what, we never want to hurt you."

"I know this. Natsuki, you can continue."

He nodded again as he returned to his previous position. He had felt that Ai was getting close to reaching climax earlier, so he shouldn't be at it much longer. Still, knowing he had to be careful, he did not just go gung-ho like he would with Syo when he gets close. He felt slender fingers running along his scalp. They were a little warm but not to a dangerous extent. He hummed lightly as Ai scratched his head gently, opening his mouth slightly so he could wrap his tongue around Ai's member.

Syo was watching the whole scene. It was always hot seeing when Natsuki gave him a blow job, but it was a different angle and a different penis that he was watching. He swallowed harshly, feeling positively aroused at the sight. "Fuck, Natsuki, at this rate, I might come just from watching this."

Natsuki pulled off of Ai and looked up at Syo. "But, I wouldn't have been able to actually make you come."

"Then, stop being so fucking sexy," Syo murmured, though he smiled to take away any harshness from his words.

Natsuki chuckled. "But, wasn't me being cute last time what made you come so quickly?"

"Oi!"

Another chuckle before he returned his attention to Ai.

Ai panted lightly as he felt his member begin to pulse. He was able to recognise the signs from earlier. "I believe I am about to eja-come. Natsuki, you're making me...c-come...ahh!"

Though Natsuki wasn't usually one to pull away, that was when it was Syo. He didn't know much about Ai's semen or if it would be toxic to ingest, so he pulled away as he felt the final pulsation. 

Syo cried out before shivering. Seeing Ai come on Natsuki had pushed him past his limit.

"Syo-chan, you really came without me touching you..." Natsuki pouted in a sulk. "But, I wanted to use my hands and mouth to make you come."

Syo panted as he came down from his climax. "S-Sorry, Natsuki. It was...too hot..."

Ai collapsed forwards and wrapped his arms around Natsuki's waist. He caught his breath as his temperature regulated itself. A second orgasm in one day. How many more times before he reached his limit? Did he have a limit? How was Natsuki's stamina? Or Syo's?

"Was it alright, Ai-chan?"

Ai nodded with a soft smile. "More than alright. Thank you, Natsuki." He sat up and turned to Syo. "I believe I owe you a kiss."

Syo nodded. He'd recovered and moved to resume the kiss from earlier.

Natsuki allowed the pout to melt away as he gently stroked himself. He had never known even visual stimulation was enough to get Syo off, even if he did prefer he did it with his hands and mouth. He watched as Syo opened his eyes and flick his gaze to the side. He understood what that meant. He shifted from his current position and moved to Syo's side. 

Syo reached down and grasped Natsuki's member, stroking it quickly. He felt his hand glide along it smoothly, courtesy of the precome leaking from the tip. He twisted his wrist on the down stroke, gripped firm while stroking upwards and always took a few seconds to use his thumb to tease the slit.

"Syo-chan...ahh!" Natsuki had already been close, so his orgasm came quickly. He felt Syo work him through his climax and watched as Syo and Ai broke from their kiss.

Ai turned in time to catch Natsuki before he collapsed. "Natsuki..."

***

It was too soon for anal. All three agreed that would come at a later time. Instead, they had formed a human centipede - Ai behind Natsuki who was behind Syo - and ground between each other's thighs, Natsuki also taking hold of Syo and stroking him at the same rhythm so he wouldn't miss out. "Syo-chan, Ai-chan...I'm already close..."

"As am I," Ai added, lightly kissing Natsuki's shoulder blade.

Syo panted. "Fuck, gonna come...yeah, right there, Natsuki..ahhh, together...!"

Grunts, groans, whimpers and eventually cries sounded from all three as they came at the same time. As they came down from their highs, they fell onto their sides and panted. It had felt amazing being with each other in such a way. They knew more was to come eventually, but for that day, that had been enough. 

Natsuki rolled onto his back and pulled the smaller pair close. He held them so they could rest their heads on his chest. "Syo-chan, Ai-chan..." He gave both of them a tender kiss, keeping it chaste. "I love both of you so much."

Syo nodded, reaching for Ai's hand and linking their fingers together. "Love ya too, Natsuki. Love ya, Ai."

Ai had found his answer. At first, he considered wanting to engage in those activities being driven by lust. But, he'd found it was more tender than just fucking each other's brains out, as Ranmaru would've phrased it. If anything, it always left him with a stronger feeling of warmth, the same he felt whenever he found his kouhai to be endearing. He kissed Syo then kissed Natsuki again. "Natsuki, Syo, I love you too. But, next time, let's have a proper date."

The blonds laughed as they nodded in agreement. "Deal," they murmured.

The trio shared more sweet kisses before fatigue hit them hard. Not breaking the embrace, not letting go of each other's hands or leaving the broad chest as a makeshift pillow, the three fell into slumber - or rather, Natsuki and Syo did while Ai engaged Sleep Mode.

**Author's Note:**

> After notes: There we go, some shameless, self-indulgent smut featuring my fave of the senpai and kouhai groupings. I am not sure if this will remain a oneshot, or if I will start a separate series for these three, only time will tell.
> 
> I headcanon that Natsuki can slip into French when aroused, though it doesn't always happen, that Syo has a voyeurism kink (he actually finds it hot when someone is watching) and he gets very mouthy when aroused.
> 
> Thanks for reading. You don't have to review, but comments and kudos are always welcome. Please don't flame.


End file.
